Recent investigations with focus on regeneration of the periodontium have studied various systems which attempt to define specific factors involved in the formation of a new connective tissue attachment. Essential biological events involved in wound healing are chemotaxis of a multitude of different cell types and subsequent proliferation and survival of a limited number of specific cell types. Extracellular matrix proteins and various polypeptide growth factors have been shown to stimulate both chemotaxis and proliferation in different systems of wound healing including periodontal repair. However, no periodontal ligament cell specific factors have as yet been isolated. Here we propose to continue to characterize and finally clone a polypeptide found in the conditioned media of PDL cells that is a specific autocrine chemoattractant and mitogen for PDL cells (PDL-CTX). Additionally, using the purified polypeptide we will examine the role that this polypeptide plays in stimulating directed migration and proliferation in conjunction with other polypeptide growth factors and extracellular matrix components. Biological response modifiers to be co-examined along with the PDL-CTX and PDL-CTX-R (PDL-CTX-receptor) include FGF, PDGF, TGF-beta and the extracellular matrix components FN and LM for their contribution to PDL chemotactic and mitogenic factor induced PDL cell movement and proliferative responses. Initial purification and partial amino acid sequence data for the PDL-CTX have been achieved. Tryptic digests will be utilized for internal amino acid sequence data. Synthetic amino acid sequences will be synthesized and tested for biological activity. Antibody to the peptide and to synthetic sequences will be raised. The PDL-CTX-R will be isolated by affinity chromatography followed by HPLC reverse phase chromatography. Amino acid composition will be preformed using Pico Tag Analysis. Sequence and peptides synthesis will be accomplished. Synthetic oligonucleotide sequences will be fabricated from the amino acid sequence of PDL-CTX. We will co-transfect whole PDL cell DNA from high responders into NIH 3T3 fibroblasts along with a transforming oncogene to ascertain if PDL-CTX is a specific chemotaxis and/or mitogenic gene. Finally, we plan to elucidate the mechanism by which PDL-CTX mediates the phenotype of PDL cells. It is our intent to establish cloned cDNAs which represent RNA molecules absent from other cell types found in the periodontium or reduced in subpopulations of PDL cells. In situ hybridization studies using CRNA probes are also planned. The identity of a few of these specific cDNA clones will be established by sequence analysis. These studies promise to significantly contribute to our understanding of periodontal connective tissue wound healing, especially the contribution mediated by the periodontal ligament cell and its product PDL-CTX.